14,389 research outputs found
Distributed lag models for hydrological data
The distributed lag model (DLM), used most prominently in air pollution studies, finds application
wherever the effect of a covariate is delayed and distributed through time. We explore the use of modified formulations
of DLMs to provide flexible varying-coeficient models with smoothness constraints, applicable in any setting in which
lagged covariates are regressed on a time-dependent response. The models are applied to simulated flow and rainfall
data and to flow data from a Scottish mountain river, with particular emphasis on approximating the relationship
between environmental covariates and flow regimes in order to detect the influence of unobserved processes. It was
found that under certain rainfall conditions some of the variability in the influence of rainfall on flow arises through
a complex interaction between antecedent ground wetness and the time-delay in rainfall. The models are able to
identify subtle changes in rainfall response, particularly in the location of peak influence in the lag structure and offer
a computationally attractive approach for fitting DLMs
Multi-particle Correlations in Quaternionic Quantum Systems
We investigate the outcomes of measurements on correlated, few-body quantum
systems described by a quaternionic quantum mechanics that allows for regions
of quaternionic curvature. We find that a multi-particle interferometry
experiment using a correlated system of four nonrelativistic, spin-half
particles has the potential to detect the presence of quaternionic curvature.
Two-body systems, however, are shown to give predictions identical to those of
standard quantum mechanics when relative angles are used in the construction of
the operators corresponding to measurements of particle spin components.Comment: REVTeX 3.0, 16 pages, no figures, UM-P-94/54, RCHEP-94/1
Assessment of methods of acquiring analyzing, and reporting crop production statistics, volume 4
There are no author-identified significant results in this report
Spectroscopy of drums and quantum billiards: perturbative and non-perturbative results
We develop powerful numerical and analytical techniques for the solution of
the Helmholtz equation on general domains. We prove two theorems: the first
theorem provides an exact formula for the ground state of an arbirtrary
membrane, while the second theorem generalizes this result to any excited state
of the membrane. We also develop a systematic perturbative scheme which can be
used to study the small deformations of a membrane of circular or square
shapes. We discuss several applications, obtaining numerical and analytical
results.Comment: 29 pages, 12 figures, 7 tabl
Topological Constraints on the Charge Distributions for the Thomson Problem
The method of Morse theory is used to analyze the distributions of unit
charges interacting through a repulsive force and constrained to move on the
surface of a sphere -- the Thomson problem. We find that, due to topological
reasons, the system may organize itself in the form of pentagonal structures.
This gives a qualitative account for the interesting ``pentagonal buttons''
discovered in recent numerical work.Comment: 10 pages; dedicated to Rafael Sorkin on his 60th birthda
The Standard Model Fermion Spectrum From Complex Projective spaces
It is shown that the quarks and leptons of the standard model, including a
right-handed neutrino, can be obtained by gauging the holonomy groups of
complex projective spaces of complex dimensions two and three. The spectrum
emerges as chiral zero modes of the Dirac operator coupled to gauge fields and
the demonstration involves an index theorem analysis on a general complex
projective space in the presence of topologically non-trivial SU(n)xU(1) gauge
fields. The construction may have applications in type IIA string theory and
non-commutative geometry.Comment: 13 pages. Typset using LaTeX and JHEP3 style files. Minor typos
correcte
Tasmanian healthcare professionals' & students' capacity for LGBTI + inclusive care: A qualitative inquiry
The health disparities and care needs of lesbian, gay, bisexual, transgender and intersex (LGBTI+) patients are becoming well known. However, healthcare practitioners (HCPs) and medical students across the Global North report limited understanding of this population and express concern about their capacity to meet the needs of LGBTI + patients. To address these gaps in literature and practice, this study draws on qualitative interviews with 12 clinicians and five health professional students exploring their understandings and approaches to LGBTI + inclusive practice in Tasmania, Australia. Through a reflexive thematic analysis, we identified that both practicing clinicians and students did not believe that their training adequately prepared them to treat LGBTI + patients. Other key barriers included reduced awareness of LGBTI + community needs due to the lack of exposure to LGBTI + patients and unfamiliarity with appropriate referral pathways in the regional Tasmanian context. Conversely, factors enabling provision of LGBTI + inclusive care included prior experience working with LGBTI + patients and establishing a network of supportive colleagues and local services. Participants who identified as LGBTI + themselves saw their personal experiences as a strength in supporting LGBTI + patients. While awareness of LGBTI + inclusive health practice is increasing, Tasmanian practitioners report insufficient training and practical difficulties with referral as key challenges
Is the propensity to emit alarm calls associated with health status?
This work was supported by the National Geographic Society, UCLA (Faculty Senate and the Division of Life Sciences), a RMBL research fellowship, and by the National Science Foundation (NSF) (IDBR-0754247, and DEB-1119660 and 1557130 to D.T.B., as well as DBI-0242960, 0731346, and 1226713 to the RMBL).Peer reviewedPublisher PD
Relaxation of strained silicon on Si0.5Ge0.5 virtual substrates
Strain relaxation has been studied in tensile strained silicon layers grown on Si0.5Ge0.5 virtual substrates, for layers many times the critical thickness, using high resolution x-ray diffraction. Layers up to 30 nm thick were found to relax less than 2% by the glide of preexisting 60° dislocations. Relaxation is limited because many of these dislocations dissociate into extended stacking faults that impede the dislocation glide. For thicker layers, nucleated microtwins were observed, which significantly increased relaxation to 14%. All these tensile strained layers are found to be much more stable than layers with comparable compressive strain
- …